Sorry for the late reply but are you saying that an old manager is effectively 'blackballing' you from other events or venues?
Though I can understand it if she/they could cause trouble at some venues - are you saying that wherever you go you're having a problem? In which case we'd be talking about someone with a hell of a lot of clout - like a female Simon Cowell!
Seriously, if you're having problems wherever you go then you need to make your peace with this person, one way or another!